Re: [PATCH] net: cgroup: fix access the unallocated memory in netpriocgroup

From: Gao feng
Date: Tue Jul 10 2012 - 05:36:25 EST


ä 2012å07æ10æ 17:15, Eric Dumazet åé:
> On Tue, 2012-07-10 at 16:53 +0800, Gao feng wrote:
>>> Hi Gao
>>>
>>> Is it still needed to call update_netdev_tables() from write_priomap() ?
>>>
>>
>> Yes, I think it's needed,because read_priomap will show all of the net devices,
>>
>> But we may add the netdev after create a netprio cgroup, so the new added netdev's
>> priomap will not be allocated. if we don't call update_netdev_tables in write_priomap,
>> we may access this unallocated memory.
>>
>
> I realize my question was not clear.
>
> If we write in write_priomap() a field of a single netdevice,
> why should we allocate memory for all netdevices on the machine ?
>
> So the question was : Do we really need to call
> update_netdev_tables(alldevs), instead of extend_netdev_table(dev)
>
>

I get it.

You are right,Indeed we only need to call extend_netdev_table
for the netdev witch we want to change.

and I read the commit f5c38208d32412d72b97a4f0d44af0eb39feb20b,
found why we need delay allocation.

I will send a v2 patch.

Thanks!
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